Cardiopulmonary Rehabilitation for a Patient with Myasthenia Gravis

A Capstone Project for PTY 768

Presented to the Faculty of the Department of Physical Therapy

Sage Graduate School

In Partial Fulfillment

of the Requirements for the Degree of

Doctor of Physical Therapy

Jennifer A. Farrell

May, 2009

Approved:

_________________________________

Laura Z Gras PT, DSc, GCS

Research Advisor

_________________________________

Marjane Selleck, PT, DPT, MS, PCS

Program Director, Doctor of Physical Therapy Program

SAGE GRADUATE SCHOOL

I hereby give permission to Sage Graduate School to use my work,

Cardiopulmonary rehabilitation for a patient with myasthenia gravis

For the following purposes:

- Place in the Sage Colleges Library collection and reproduce for Interlibrary Loan.

- Keep in the Program office or library for use by students, faculty,

or staff.

- Reproduce for distribution to other students, faculty, or staff.

- Show to other students, faculty or outside individuals, such as accreditors

or licensing agencies, as an example of student work.

- Use as a resource for professional or academic work by faculty or staff.

Jennifer A. Farrell Date

[We or I] represent to The Sage Colleges that this project and abstract are the original work

of the author[(s)], and do not infringe on the copyright or other rights of others.

Cardiopulmonary rehabilitation for a patient with myasthenia gravis

________________________________________________________________________

Jennifer A. Farrell Date

Abstract: Purpose: The purpose of this case study was to determine the effects of a 13 week

physical therapy cardiopulmonary endurance program on aerobic capacity, and muscle

strength in a patient with myasthenia gravis (MG). Methods: The patient was a 61 year old

female who presented to the clinic with generalized muscle weakness and decreased aerobic

capacity. The patient reported to the outpatient physical therapy clinic 3 times a week for a

total of 13 weeks with an average session time of 60 minutes. Rate of Perceived Exertion

(RPE), heart rate, blood pressure, and EKG monitoring occurred throughout the physical

therapy sessions. Results: Before premature discharge from physical therapy secondary to

emergency surgery for reversal of colostomy, the patient demonstrated tolerances to aerobic

activity as evidenced by a reduced heart rate during activity, and also lower ratings on the

RPE during exercise. The patient also subjectively reported enjoyment of the program and

also had greater self-esteem with functional ADLS and IADLS. Conclusion: This data

suggests that a physical therapy cardiopulmonary endurance training may promote gains in

functional ADL’s and IADL’s, gross motor strength, and aerobic capacity in patients with

MG.

Keywords: myasthenia gravis, cardiopulmonary rehabilitation, aerobic capacity, fatigue,

muscle weakness, endurance

3

Introduction

Myasthenia gravis (MG) is classified as a neuromuscular transmission disorder

caused by antibody-mediated blockade of muscle nicotinic acetylcholine receptors.1 MG

affects 2 to 7 out of every 10,000 in western countries, occurring one and half times more

often in women than in men.2 Early in its course, MG tends to target ocular muscles affecting

eye and facial movement which in 75% to 90% of patients leads to generalized MG.

Symptoms of ophthalmoparesis includes diplopia, and ptosis.3 MG becomes generalized

usually within 3 years after onset of ocular degeneration. In 85% of the patients, axial

muscular groups, coupled with facial and bulbar musculature are primarily affected first

causing loss of facial expressions, speech impairments, mastication and swallowing

problems.4 MG is characterized by weakness of voluntary muscles; repetitive activity

heightens this response.5 Muscle weakness and fatigue target proximal muscle groups more

so than distal muscle groups, causing significant loss of functional activity in patients with

MG.6

Patients diagnosed with MG have a decrease in respiratory strength and endurance.

Respiratory muscle degeneration results in compensatory breathing patterns. Inspiratory

muscle training has been linked to improving respiratory muscle function in illnesses in

which muscular weakness determines morbidity and mortality.6 Patients with MG may have

a reduction of maximal voluntary ventilation (MVP) at rest. Patients who have MG have a

decreased ability to sustain increased ventilation with physical activity may be reduced.

Additional deterioration of the patient’s functional capacity may result in respiratory failure.

Bronchopneumonia and other infections are the most common precipitating factors for

respiratory failure.7 It is suggested that improvement in muscle function should be focused on

4

in therapy.8 A small number of studies have concluded the effects of respiratory muscle

training in patients with MG, suggesting that resistive inspiratory muscle training coupled

with specific expiratory muscle training resulted in a significant increase in respiratory

muscle strength and endurance as well as alleviation of dyspnea.9

The pharmacological management of MG is targeted at minimizing the autoimmune

response and maximizing acetylcholine (ACH). Research has shown that moderate daily

doses of prednisone in patients with MG for 4-6 weeks, followed by low dose alternate day

therapy as needed, controlled diplopia.10

Pyridostigmine is a long acting reversible

acetylcholinesterase inhibitor. ACH inhibitors increase the amount of available ACH in the

junction leading to contractility gains. ACH inhibitors lead to enhanced cholinergic activities

tissues and major organs other than skeletal muscles. Enhanced cholinergic activity

elsewhere can lead bronchospasm, bradycardia, salivation, hidrosis, miosis, nausea, and

diarrhea.4 In addition to the primary line of pharmacological treatment, immunosuppressive

are often prescribed. Examples of immunosuppressive drugs include corticosteroids,

azathioprine, cyclophosphamide, cyclosporine, and meteorite.4 Corticosteroids work to

decrease autoantibody synthesis, and are effective in 80% of patients.10

Immunosuppressive

drugs target many areas of the immune system inhibiting cellular and hormonal mechanisms

which in turn reduces damage caused by MG.4

Exercise prescription principles in the management of neuromuscular disorders

involve maintenance management of muscle strength within the limitations caused by the

disease process to minimize atrophy. Exercise may be beneficial in slowly progressive

neuromuscular diseases such as MG. Research suggests that low impact aerobic exercise is

an effective management strategy for some people with MG. Prescriptive walking programs

5

have decreased patient fatigue, and also encouraged patients to return to previous activities.3

Physiological benefits received from walking include increased number and density of

mitochondria, along with skeletal mass increase.11

Walking benefits stem further than

physiological affects, other benefits include improved body image, mood, and well being.3

A study completed by Normandin et al12

, suggests that exercise training is a necessary

component in the comprehensive pulmonary training in patients with respiratory disorders

such as COPD. The study concludes, both high intensity and lower extremity endurance

training and low intensity calisthenics led to similar short term improvements in

questionnaire related dyspnea functional performance, and health status. No significant

difference was suggested when comparing unsupported and supported arm exercise in

patients with severe chronic airflow obstruction. However, the 12 Minute Walk Test, bicycle

ergometer power output, and respiratory muscle function improved.12

Martinez et al13

suggest pulmonary rehabilitation programs improves lower extremity strength and

respiratory muscle function. Also, arm exercise training will result in greater increases in

unsupported arm activity.13

The beneficial effects of strength training, endurance training,

and a combination training of both on dyspnea and quality of life in patients with decreased

respiratory capacity. Improvements persisted 3 months after the intervention training.

Increases in sub maximal exercise capacity for the endurance group were significantly higher

than those in the strength group, but were similar in magnitude to the combined training

group.14

Examining the efficacy of program utilizing symptom limited interval training

combined with strength training suggests significant increases in six minute walk results,

peak exercise tolerance, and quality of life.15

6

Skeie et al16

, reported respiratory muscle training and strength training in patients

with MG beneficial. A study completed in 2000, suggested that resistance exercise plus

creatine supplementation promote gains in strength and fat-free mass in patients with MG.17

Persistent muscular weakness, fatigue, and respiratory impairments are the primary

physical characteristics of this disease, however, impairments stem further into other aspects

of life such as psychological and family problems. The combination of those factors is

potentially lethal to the patient’s health-related quality of life. The relationship between lung

function and health-related quality of life are directly related. Concluding, increased muscle

deterioration and respiration will result in a lower perceived quality of life.18

Muscle

weakness, fatigue, and respiratory impairments are also contributing factors to decreased

quality of life in patients who have MG.

Outcome Measures

The Six Minute Walk Test (SMWT) is used as a clinical indicator of functional

capacity in patients with cardiopulmonary impairments.19

The SMWT is often used in

clinical practice and studies of cardiopulmonary rehabilitation because it relates better with

symptoms and quality of life than most maximum exercise tests. It is also used in

cardiopulmonary rehabilitation programs as an outcome measure to determine the effects of

exercise training on functional exercise capacity.20

Research has supported a significant

increase in walking distance when a SMWT was performed a second time after completion

of cardiopulmonary rehabilitation program. The increase in the SMWT distance ranged from

7% to 14.9% after completion of the cardiopulmonary rehabilitation program.20

In the

SMWT the patient is asked to walk as far as he/she could in 6 minutes, at a comfortable

walking pace. Vitals are taken before midway and after the SMWT. The SMWT is useful in

7

the assessment of cardio pulmonary rehabilitation therapy, the tests also has a greater value

in patients with more advanced disease processes.21

Pulse Oximetry

Measurement of respiratory gas exchange during exercise is essential in

cardiopulmonary rehabilitation. Changes in blood oxygenation are useful in detecting lung

disease by evaluating the response to therapy.22

Pulse oximeters are commonly used during

exercise in clinical and research settings to provide a noninvasive, continuous estimate of the

oxyhemoglobin.23

Oxygen saturation measurements are taken before during and after each

intervention. If oxygen saturation dropped below 88% exercise needs to be stopped

immediately. Based on recommendations of the Nocturnal Oxygen therapy Trial24

,

supplemental O2 is indicated for patients with a SAO2 of 88% while breathing room air. The

same guidelines apply when considering supplemental oxygen during exercise training. The

flow rate for O2 should be titrated to maintain SAO2 at 90% or more throughout the

training.24

Rate of Perceived Exertion

The Borg CR-10 rating scale was applied to assess perceived exertion before, during,

and following interventions. The Borg CR-10 is a 10-point psychophysical assessment scale,

where 0 represents “nothing at all” and 10 “maximal”. The subject used this 10-point scale to

express the total feeling of exertion which combines all sensation and feeling of physical

stress, effort, and fatigue.25

Rating of perceived exertion (RPE) which is a scale of ratings

ranging between 6 to 20, with 6 being no exertion at all, and 20 being equivalent to maximal

exertion. Perceived exertions ratings from 12-14 suggests that cardiovascular activity is being

performed at a moderate level of intensity.26

RPE scales have been traditionally used as a

8

subjective index of exercise intensity for both exercise testing and exercise prescription. Hu

et al.27

, report that RPE during exercise changed in both a linear and quadratic manner as

intensity increased. Also, self- assessment was a predictor of both patterns of change. The

use of RPE measures in an exercise prescription in older adults suggests that exercise self-

efficacy is implicated in patterns of RPE change.27

The day to day variability between the

lactate to RPE and did not vary substantially over a three day period. These results suggest

that the RPE is a reliable, useful, and practical marker that can be used to monitor training.28

Objective monitoring purposes suggest both healthy individuals, and individuals with

cardiopulmonary disorders, should train at a target heart rate (THR), in order to exercise in a

safe range, and to attain appropriate training responses. Traditionally, when prescribing

exercise for patient’s with cardiac and or pulmonary conditions the HR has been used as an

estimate of intensity, because of the linear relationship between HR and minute oxygen

consumption (VO2 ) during incremental exercise.29

VO2 maximum is directly related to

frequency of intensity training. VO2 improvements for normal healthy individuals usually

range between 10-15%. Results with greater than 30% increase in VO2 max are typically

occurring in individuals with larger losses of total body mass, in cardiac patients, and patients

with low initials level of fitness.30

Maximal HR is most commonly used as a basis for

prescribing exercise intensity in both rehabilitation and disease prevention programs.31

Maximal HR is also used a criterion for achieving peak exertion in the determination of

maximal aerobic capacity. Hirofumi, Monahan, and Douglas32

suggest, the age predicted

equation for calculating Maximal HR (220-age), is predicted by age alone, and is

independent of gender and physical activity status. Furthermore, it has an effect of the

underestimating the true level of physical stress imposed, during exercise intensity.

9

Therefore, aerobic exercise interventions, based on traditional methods, would result in a

target heart rate below the recommended intensity for achieving optimal gains and health

benefits.32

The purpose of this study was to examine the functional outcomes of a

cardiopulmonary rehabilitation program for a patient with MG to improve aerobic capacity,

strength, SMWT distances, and self-reported quality of life. This study was approved by the

Institutional Review Board at The Sage Colleges in Troy, NY.

Case Description

Medical History/Risk Factors

Patient (pt) is a 61 year old female diagnosed with MG and was symptomatic

presenting with muscle weakness and debility. The pt was treated in an outpatient

cardiopulmonary unit. Past medical history includes colostomy, hiatal hernia with, gastro-

esophageal reflux disease, high blood pressure and melanoma of the right hip. The pt also

reports being physically inactive, deconditioned and experiences labored breathing on

exertion. The pt currently denies any pain. The pt is currently taking Cellcept for

prophylaxis of organ rejection which can occur in patients receiving allergenic renal, cardiac

or hepatic transplants, Prednisone for suppressing the immune system and inflammatory

response, Fosamax for prevention postmenopausal osteoporosis and steroid-induced

osteoporosis, Lopressor for high blood pressure, and Zoloft for treatment of depression and

anxiety as prescribed by her primary physician.

Examination

Tests and Measures

The pt’s resting blood pressure was 132/74, heart rate was 81 beats per minute, and

hemoglobin oxygen saturation (SaO2) was 95%. The patient weighed 186 pounds and was

10

5’3” tall. The patient ambulated independently with an antalgic gait pattern, with decreased

anterior advancement of bilateral tibias. The patient had a decreased step length, increased

stride variability, and decreased cadence. The patient was able to transfer from sit to stand

independently with use of chair armrests. The patient was able to transfer from supine to sit

independently with excessive compensatory strategies, and increased upper extremity

dependency. The patient was able to transfer from stand to sit with independently with

decreased eccentric core control.

Six Minute Walk Test Values

The pt performed the SMWT in the physical therapy department. The patient’s

resting HR,BP and SaO2 was 86bpm, 132/74, and 95% respectively. The pt’s HR, BP, and

SaO2 were 92 bpm, 128/80, and 97% respectively when measured at 3 minutes. The pt

reported mild SOB at 5:20. After completion of the SMWT the pt’s HR, BP, and SaO2 were

83 bpm, 120/72, and 95%. The pt ambulated a total of 1050ft and rated 15/20 on the RPE.

EKG and Target Heart Rates:

The THR of the patient was established prior to the start of every intervention

session. The THR was achieved by adding 20-30 bpm above the pt’s resting HR. The THR

was also re-established prior to the start of each additional intervention. During intervention

week 1, session 1, the pt’s THR throughout the duration of the cardiopulmonary

interventions was 70-130 bpm (Figure 1). Intervention week 4, session 12, the THR

throughout the intervention period was established at 98-108 bpm (Figure 2). Intervention

week 8, session 23, the THR throughout the intervention period was also 98-108 bpm (Figure

3).

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Functional Limitations

The pt reported that her walking speed was decreasing and it was noticeable in

everyday activities especially grocery shopping. The pt also reported having trouble with

home maintenance such as working in her garden, taking care of her lawn, and household

cleaning. Due to reported limitations in breathing the patient reported taking longer breaks

during meal preparation. Due to muscle debility and shortness of breath the pt also has

decreased her travel to places outside of her home.

Evaluation

The pt presented to the clinic with decreased aerobic tolerance to exercise as

evidenced by reaching maximum heart rate with minimal exercise. The pt also had gross

motor weakness in the bilateral upper and lower extremities. The pt ambulated 1050ft during

the SMWT. The pt’s reported functional limitations include; increased bouts of SOB,

decreased ability to perform ADL’s, decreased ability to partake in recreational activities,

decreased walking distance, decreased ability to exercise.

Diagnosis

The pt was placed into the Guide to Physical Therapist’s Practice Preferred Practice

Pattern 6B: Impaired Aerobic Capacity/Endurance Associated with Deconditioning.33

Prognosis

MG is a neuromuscular disorder commonly precipitates respiratory failure, despite

underlying primary lung disease. Due to the nature of the disorder, the patient’s prognosis is

fair when considering MG disease process and relative co-morbidities.

12

Plan of Care

The pt was seen in the outpatient cardiopulmonary unit 3 times a week for 13 weeks

which included a pre-mature discharge secondary to reversal of colostomy surgery.

Short Term Goals:

Pt will increase tolerance to aerobic capacity by regulating HR throughout treatment sessions

in 4 weeks.

Pt will improve the SMWT from 1050 feet to 1500 feet in 4 weeks.

Pt will self monitor heart rate and pulse oximetry in 4 weeks.

Long Term Goals

Pt will improve the SMWT from 1050 feet to 2000 feet in 12 weeks.

Pt will return to her level of prior function regarding daily activities, recreational activities, or

occupational functions in 12 weeks.

Pt will have a higher quality of life as measured by the questionnaire in 12 weeks.

Intervention

The pt enrolled in cardiopulmonary physical rehabilitation program at an outpatient

setting in July of 2008. A target heart rate (HR) was established of 20-30 beats per minute

above resting heart rate (RHR). Each session was approximately one hour in length including

warm up and cool down. Initial interventions began at low level settings, and minimal time

durations, progressing through the programs levels and time were increased as per pt

tolerance. During the first 8 sessions the pt completed the following therapeutic exercises

with EKG monitoring; NU-STEP Recumbent Stepper (NS), Upper Body Cycle (UBC),

Rower (R), Chest Press (CP), and treadmill (TM). All of the above exercises increase

cardiovascular endurance, and promote strengthening of associated musculature (see Table).

13

Strength training was performed using the patient’s own body weight with the

addition of dumbbells, and thera-bands as tolerated. The specific strengthening techniques

used were the chest press and the upper extremity row. Initially the patient completed 10

repetitions of each exercise for 3 sets. Initially the patient was able to tolerate the upper

extremity row using 15 pounds completing 3 sets of 10 repetitions with a RPE of 13. The

patient also initially completed the chest press using a weight of 10 pounds completing 3 sets

of 10 repetitions with a RPE of 14. The patient was able to progress to 3 sets of 15

repetitions lifting the same weight for the upper extremity row, and the chest press at

intervention week 4. The progression was made according to the patient’s subjective reports

of RPE, which decreased to 10 by intervention week 3. The upper extremity row and chest

press were held from intervention week 5 to intervention week 8 secondary to patient fatigue,

and request. Weight training was not again incorporated in the exercise regime secondary to

premature discharge of the program due to co-morbidities.

Cardiovascular endurance was targeted by having the pt exercise on the motorized

TM, NS, and the UBC. Initially the patient completed 5 minutes on each the NS, and UBC.

During the initial introduction to the cardiovascular endurance equipment the patient’s RPE

for all 3 activities was 14. The TM was added in session 2 when the patient was asked to

walk at 1.5-2.0 mph for 5 minutes. The patient was able to increase duration on the Nu-step

to 15 minutes L2 , the UBC to 6 minutes 60/40, and the TM to 10 minutes, with an overall

RPE of 13, and SOB of 4, during intervention week 2. Intervention week 4, the patient was

able to increase durations of the TM to 20 minutes with a walking speed of 2.0 mph, The

UBC to 10 minutes, and the Nu-step to 25 minutes at Level 3 with a RPE of 13 and a SOB of

4. During this session the patient also reported SOB of 1 secondary to humidity. Increases

14

again were added to the duration of cardiovascular exercise in intervention week 6. The pt

completed 30 minutes on the TM with a 2.2 mph walking speed, 12 minutes on the UBC

with an increased resistance from 60/40 to 70/50, and 30 minutes on the Nu-Step level 4.

During intervention week 8 the pt’s RPE was 15 with reported SOB of 2 while on the Nu-

step. The final session of the cardiopulmonary rehabilitation program completed by the

patient was during week 8, session 23. The patient completed 25 minutes on the TM at level

2.5 mph walking speed, 25 minutes on the Nu-Step level 5, with a RPE of 13. 5 minutes were

completed on the UBC level 70/50 with a reported RPE of 16. The patient reported that she

enjoyed the program and it gave her great motivation. The pt called to cancel her next

scheduled appointment secondary to having an emergency reversal of colostomy surgery.

Cardiovascular exercise intensity was increased by increasing the duration, and increasing

the walking speed while walking on the TM, also increasing pedaling resistance on the NS,

and upper body resistance on the UBC. The intensity was increased as patient tolerated

measured by the Rate of Perceived Exertion (RPE).26

HR, BP, SaO2, and EKG readings were

monitored while the patient was participating in the exercise program.

Educational topics covered during visits included: overview of MG and muscle

debility, energy conservation techniques with activities of daily living, and biomechanics

associated with activities of daily living.

Outcomes

The pt was unable to complete the 12 week cardiopulmonary rehabilitation secondary

to emergency reversal of colostomy surgery. The pt completed 8 weeks of the

cardiopulmonary rehabilitation program. The pt improved tolerance to aerobic activity,

15

increased in functional mobility, increased walking distance, and decreased shortness of

breath with ADL’s and IADL’s.

Discussion

The effects of rehabilitation on MG in the literature are minimal. Patients with

neuromuscular diseases nonspecific to MG have positive projected outcomes when treated in

the clinic.15

Based on the available literature high intensity training appears to be an

advantage with patients who require pulmonary rehabilitation.34

A patient with MG who also

has a restrictive pulmonary complication is considered at risk for succumbing to reduced

mobility and other negatively associated cardiopulmonary problems.35

Further, without

proper intervention neuromuscular conditions lead to progressive deterioration of respiratory

musculature.36

The goal of cardiopulmonary rehabilitation is to prevent the need for

mechanical ventilation because their prognosis for weaning once cardio-respiratory failure

has occurred is poor. Patients with associated neuromuscular disorders are living longer,

secondary to preventative cardiopulmonary rehabilitation. Therefore, the already weakened

cardiopulmonary insufficiency will be heightened by age related changes.37

The pt presented similarly to the findings of Keenan, et al1, displaying muscle weakness

and fatigue primarily in the proximal muscle groups, with significant loss of daily functional

activities. Subjectively, the pt reported increased in tolerance to daily activities, such as

grocery shopping, cleaning, preparing meals, and walking after completion of an 8 week

cardiopulmonary rehabilitation.

Throughout the 8 week rehabilitation program the pt’s complaints of dyspnea declined.

The pt initially presented with decreased ability to sustain increased ventilation during

16

functional activities, however, upon completion the pt’s ability to sustain increased

ventilation during most functional activities increased.

According to Davidson, et al3, exercise prescription in the management of neuromuscular

diseases should be directed to management of muscle strength, coupled with low impact

aerobic exercise to slow the progressive of the disease. The pt completed both low impact

aerobic exercise and muscle strengthening. The pt’s results after 8 weeks of the program

included increased functional mobility, and increased tolerance to aerobic and strengthening

exercise.

The beneficial effects of strength training, endurance training, and a combination of

training of both have increased quality of life in pt’s with decreased respiratory capacity

according to Martinez, et al13

. After completion of the 8-week cardiopulmonary rehabilitation

program the pt increased quality life verbally with examples of being able to play with her

grandchildren, taking her dogs for walks, and increased appreciation for health and wellness.

In comparison to the entry of the program, with pt reported decreased quality of life, and

decreased tolerance to functional activities, and reported bouts of depression secondary to

low self-esteem.

Baseline THR’s were established prior to each treatment session, as well as prior to each

intervention. Intervention week 1, session, 1 the pt’s THR was ranged 70-130 bpm. The wide

range of accepted THR was secondary to the pt’s decreased tolerance to aerobic and strength

training exercises and the decreased ability of the heart to respond to increased

intensity(Figure 1). This finding is congruent with the findings of Klissouras et al30

, in that

pt’s with initial low levels of fitness will also have increased variability of corresponding

HR’s, secondary to decreased tolerance to exercise. Intervention week 4, session 12, THR’s

17

range was from 98-108 bpm(Figure 2). The pt was able to achieve and maintain the THR

throughout the entire intervention session. Roberto et al29

, suggest training at within the set

range of the THR, allows pt’s to exercise safely, and still attain a benefits from training

responses. Intervention week 8, session 23, the pt’s THR range was between 98 bpm and 108

bpm (Figure 3). During this session the pt’s HR was variable and the pt rarely trained within

the suggested THR range. The variability in HR’s achieved during this intervention session

could have been due physiological processes secondary to co-morbidities beyond the scope

of the cardiopulmonary intervention. After session 23 the pt was admitted into the hospital to

have a reversal of colostomy surgery. The pt was discharged from the cardiopulmonary

physical therapy rehabilitation program, secondary to the change in the pt’s health status.

Limitations to this study included pre-mature discharge secondary to surgery for

reversal of colostomy. The SMWT was not performed before discharge, therefore limiting

the objective data in this study. A quality of life questionnaire may have been used to

objectively document increases in quality of life and self-worth.

Future studies should include, a larger sample size, along with control and treatment

groups. The population should not be a sample of convenience, but rather a sample selected

from specific inclusion/exclusion criteria. The research should address functional capacity,

along with aerobic tolerance to activity. Also the research should also focus on pt reported

quality of life.

Conclusion

Pt’s with generalized MG may benefit from cardiopulmonary rehabilitation in the

following ways; increased tolerance to aerobic activity, increased walking distances,

18

increased functional mobility, decreased bouts of shortness of breath, and increased strength

of the cardiopulmonary system.

19

References

1. Keenan S, Alexander D, Road J, Ryan C, Oger J, Wilcox P. Ventillatory muscle

strength and endurance in myasthenia gravis. Eur Repir J. 1995;8:1130-1135.

2. Facts about myasthenia gravis (MG). Muscular Dystrophy Association. 2006.

Available at: http://www.mda.org/publications/fa-mg-qa.html. Accessed April 19,

2009.

3. Davidson L, Hale L, Mulligan H. Exercise prescription in the physiotherapeutic

management of myasthenia gravis: a case report. NZ Journal of Physiotherapy.

2005;33(1):13-17.

4. Romi F, Gilhus N, Aarli J. Myasthenia gravis: clinical, immunological, and

therapeutic advances. Acta Neurol Scand. 2005;111:124-141.

5. Kelly B, Luce J. The diagnosis and management of neuromuscular disease causing

respiratory failure. CHEST. 1991;99:1485-1494.

6. Fregonezi G, Resqueti V, Guell R, Pradas J, Casan P. Effects of 8-week, interval

based inspiratory muscle training and breathing retraining in patients with generalized

myasthenia gravis. CHEST. 2005;128:1524-1530.

7. Murthy J, Meena A, Chowdary G, Naryanan J. Myasthenic crisis: clinical features,

complications and mortality. Neurol India. 2005. 53;37-40.

8. Rassler B, Hallebach G, Kalischewski P, Baumann I, Schauer J, Spengler C. The

effect of respiratory muscle endurance training in patients with myasthenia gravis.

Neuromuscular Disorders. 2007;17:385-391.

9. Weiner P, Gross D, Meiner Z, Ganem R, Weiner M, Zamir D, et al. Respiratory

muscle training in patients with moderate to severe myasthenia gravis. Can J Neurol

Sci. 1998;25:236-241.

10. Kupersmith M, Moster M, Buhyian S, Warren F, Weinberg H. Beneficial effects of

corticosteroids on ocular myasthenia gravis. Arch Neurol. 1996;53(8): 802-804.

11. McDonald C. Physical activity, health impairments, and disability in neuromuscular

disease. Am J Phys Med Rehabil. 2002;81(11):108-120.

12. Normandin E, McCusker C, Connors M, Vale F, Gerardi D, ZuWallack R. An

Evaluation of two approachers to exercise conditioning in pulmonary rehabilitation.

CHEST. 2002;121:1085-1091.

13. Martinez F, Vogel P, Dupont D, Stanopoulous I, Gray A, Beamis J. Supported arm

exercise vs unsupported arm exercise in the rehabilitation of patients with severe

chronic airflow obstruction. CHEST. 1993;103:1397-1402.

14. Ortega F, Toral J, Cejudo P, Villagomez R, Sanchez H, Castillo J, Montemayor T.

Comparison of effects of strength and endurance training in patients with chronic

obstructive pulmonary disease. Am J Respir Crit Care Med. 2002;166:669-674.

15. Kaelin M, Swank A, Barnard K, Adams K, Beach P, Newman J. Physical fitness and

quality of life outcomes in a pulmonary rehabilitation program utilizing symptom

limited interval training and resistance training. JEP. 2001;4(3):30-37.

16. Skeie G, Apostolski S, Evoli A, Gilhus N, Hart I, Harms L, Jones D, Melms A,

Verchuuren J, Horge H. Guidelines for the treatment of autoimmune neuromuscular

transmission disorders. European Journal of Neurology. 2006;13:691-699.

20

17. Stout J, Exkerson J, May E, Coulter C, Popvich G. Effects of resistance exercise and

creatine supplementation on myasthenia gravis: a case study. Med. Sci. Sports Exerc.

2001;33(6):869-872.

18. Fregonezi F, Resqueti V, Pradas J, Vigil L, Casan P. The relationship between lung

function and health-related quality of life in patients with generalized myasthenia

gravis. Arch Bronconeumol. 2006;42(5):218-224.

19. Stevens D, Elpern E, Sharma K, Szidon P, Ankin M, Kesten S. Comparison of

hallway and treadmill six-minute walk tests. Am J Respir Crit Care Med.

1999;160:1540-1543.

20. Spencer L, Alison J, McKeough Z. Six minute walk test as an outcome measure. Am.

J. Phys. Med. Rehabil. 2007;87(3):224-228.

21. Olsson L, Swedberg K, Clark A, Witte K, Cleland J. Six minute walk test as an

outcome measure for the assessment of treatment in randomized, blinded intervention

trials of chronic heart failure: a systematic review. European Heart Journal.

2005;26:778-793.

22. Escourrou P, Delaperche M, Visseaux A. Reliability of pulse oximetry during

exercise in pulmonary patients. CHEST. 1990;97: 635-638.

23. Mengelkoch L, Martin D, Lawler J. A review of the principles of pulse oximetry and

accuracy of pulse oximeter estimates during exercise. Phys Ther. 1994;74(1):40-49.

24. Demets D, Williams G, Brown B. A case report of data monitoring experience: the

nocturnal oxygen therapy trial. Control Clin Trials. 1982;3(2): 113-124.

25. Chui M, Wang M. the effect of gait speed and gender of perceived exertion, muscle

activity, joint motion of lower extremity, ground reaction force and heart rate during

normal walking. Gait and Posture. 2007;25:385-392.

26. Borg G. Borg’s perceived exertion and pain scales. Illinois. Human Kinetics; 1998.

27. Hu L, McAuley E, Motl R, Konopack J. Influence of self-efficacy on the functional

relationship between ratings of perceived exertion and exercise intensity.

JCRP.2007;27:303-308.

28. Duke J, Behr M, Ondrak K, Hackney A. Day-to-day variability of the lactate-to-rating

of perceived exertion ration. Physical Education and Sport. 2008; 52:30-34.

29. Roberto M, Ward J, Lentine T, Mahler D. Target dyspena ratings predict expected

oxygen consumption as well as target heart rate values. Am J Respir Crit Care Med.

1999; 159: 1485-1489.

30. Klissovras V, Pirnay F, Petit J. Adaptation to maximal effort: genetics and age. J.

Appl. Physiol. 1973.35; 288-293.

31. Fletcher G. How to implement physical activity in primary and secondary prevention:

a statement for healthcare professionals from the Task Force on Risk Reduction,

American Heart Association. Circulation 1997;96:355-357.

32. Tanka H, Monahan K, Seals D. Age-Predicted maximal heart rate revisited. JACC.

2001;37(1):153-156.

33. American Physical Therapy Association. Guide to Physical Therapist Practice. 2nd

ed. Alexandria, VA: APTA; 2003.

34. Casaburi R, Patessio A, Ioli F, et al. Reductions in exercise lactic acidosis and

ventilation as a result of exercise training in patients with obstructive lung disease.

Am Rev Respir Dis. 1991;143:9-18.

21

35. Wong W. Physical therapy for a patient in acute respiratory failure. Phys Ther. 2000;

80(7): 662-670.

36. Black L, Hyatt R. Maximal static respiratory pressures in generalized neuromuscular

disease. Am Rev Respir Dis. 1971;103:641-650.

37. Dean E. Oxygen transport deficits in systemic disease and implications for physical

therapy. Phys Ther.1997;79:476-487.

22

Table. Cardiopulmonary Rehabilitation

Intervention

Weeks 2 3 4 5 6 7 8

Recumbent Stepper

15', L2 16',L2 25',L3 25',L3

30',L4

25',L5 25',L5

Upper Body Cycle 6', 60/40 6', 60/40 10',60/40 10',60/40 12',70/50 15',70/50 5',70/50

Treadmill

10',

2.0mph

15',

2.0mph 20',2.0mph 20',2.0mph 30',2.2mph 30',2.2mph 25',2.5mph

Upper Extremity

Row

3x10,

15#

3x10,

15# 3x15,15#

Chest Press

3x10,

10#

3x10,

10# 3x15,10#

23

Figure 1. HR Variable Prior to PT.

Figure 2. HR Stable after 4 Weeks of PT

Figure 3. HR Variable at Week 8